Why does my program reach end of file when I input larger numbers?

int main()
{
    int sum = 0, value = 0;
    while (std::cin >> value)
        sum += value;
    std::cout << "Sum is: " << sum << std::endl;
    return 0;
}

So this code takes values from the user and adds them. I don't understand what makes it reach end of file. I tested it multiple times and found that when I use larger numbers (9999999999) it ends faster, but when I put in just 1s it never ends.